RAPID: Hurricane Impact on Phytoplankton Community Dynamics and Metabolic Response

飓风哈维是几十年来袭击德克萨斯州海岸的最强飓风，由此产生的潮汐潮，洪水和陆地径流对沿海海洋产生了严重影响。浮游植物是食物链中的第一个环节，其受到的影响可能是前所未有的。为了确定浮游植物群落将如何应对盐度、营养物输入和潜在毒素的急剧变化，立即和连续采样是充分捕捉影响并确定条件何时恢复“正常”的唯一途径。在得克萨斯州海岸部署的自动化、连续的浮游植物成像仪器记录了浮游植物的图像，并允许计算不同物种的丰度。该项目的成果与已被“打开”或表达的基因的分子信息一起，将有助于确定各种浮游植物的反应。随着未来气候变化，预计极端风暴的频率将增加，因此，现在确定的应对措施将有助于预测此类事件将如何影响这些初级生产者，而这些初级生产者又支持海洋生态系统中的大多数食物网，来自成像FlowCytobot（IFCB）的高时间分辨率观测研究表明，墨西哥湾的飓风会导致浮游植物群落结构发生剧烈变化。 这个快速项目的目标是：1）描述浮游植物物种的动态与德克萨斯州海岸沿着环境变量的关系; 2）评估浮游植物群落的短期和长期变化; 3）确定浮游植物群落获取资源的策略。为实现这些目标，本项目将利用国际森林生物多样性论坛的时间序列跟踪哈维飓风后恢复期间的浮游植物群落结构。此外，还进行了两次快速响应巡航（9月底和10月初），在从加尔维斯顿到德克萨斯州阿兰瑟斯港的一个样带沿线的5个沿着地点进行采样。在每个站点，将收集CTD剖面和来自表面和叶绿素最大值的水样，用于营养、碳酸盐化学和RNA测序，以进行元转录组学分析。元转录组学可以提供一个指示的代谢策略和功能的浮游生物群落内响应环境的变化。元转录组学方法的优点是捕获了对环境的整个分子反应。因此，虽然浮游植物对洪水径流增加的营养输入的反应是有针对性的，但对其他环境压力（有毒物质，缺氧，酸化）的反应也被捕获。使用多变量统计技术，如主成分分析（PCA）和网络分析，一个强大的技术，用于确定类群之间的潜在相互作用，这一时间序列的分析将提供洞察力的环境因素和代谢反应结构的社区在飓风过后。

Hurricane Harvey is the strongest hurricane to hit the Texas coast in decades and the resulting tidal surges, flooding and terrestrial runoff have had a severe impact on the coastal ocean. The effects on the phytoplankton, the first link in the food chain, may be unprecedented. To determine how the phytoplankton community will respond to such drastic changes in salinity, nutrient inputs, and potential toxins, immediate and continuous sampling is the only way to fully capture the effects and to identify when conditions return to "normal". An automated, continuous phytoplankton imaging instrument that is deployed on the Texas coast records images of the phytoplankton and permits calculation of the abundance of different species. Together with molecular information on the genes that have been "turned on", or expressed, outcomes of this project will help determine the responses of individual types of phytoplankton. Extreme storms are expected to increase in frequency with future climate change, so the responses identified now will be valuable in predicting how such events will affect these primary producers, which in turn support most of the food webs in marine ecosystems, in the future.High temporal resolution observations from the Imaging FlowCytobot (IFCB) have revealed that hurricanes in the Gulf of Mexico cause drastic changes in the phytoplankton community structure. The objectives of this RAPID project are: 1) to characterize the dynamics of the phytoplankton species in relation to the environmental variables along the Texas coast; 2) to assess the short and long-term changes in the phytoplankton community; and 3) to identify the strategies of the phytoplankton community for resource acquisition. To accomplish these objectives, this project will utilize IFCB time series to follow phytoplankton community structure during the recovery period from Hurricane Harvey. In addition, two RAPID response cruises (in late September and early October) to sample at 5 sites along a transect from Galveston to Port Aransas, TX. At each station, CTD profiles and water samples from surface and the chlorophyll maximum will be collected for nutrients, carbonate chemistry, and RNA sequencing for metatranscriptomic analysis. Metatranscriptomics can provide an indication of the metabolic strategies employed and functional relationships within the plankton community in response to changes in the environment. The advantage of a metatranscriptomic approach is that the entire molecular response to the environment is captured. So, while the response of phytoplankton to increased nutrient inputs from floodwater runoff is targeted, the responses to other environmental stresses (toxics, hypoxia, acidification) are also captured. Analyses of this time series using multivariate statistical techniques, such as principal component analysis (PCA), and network analysis, a powerful technique for identifying potential interactions among taxa, will provide insights on the environmental factors and metabolic responses structuring the community during the aftermath of the hurricane.